Quantum scattering calculations of the O(D-1) plus HCl reaction using a new ab initio potential and extensions of J-shifting

We report results of quantum wave packet calculations of the O(D-1)+HCl(v=0 ,j)--> ClO+H, OH+Cl, reactions for zero and nonzero total angular momentum, J, (using the centrifugal sudden approximation), and using a new fit to ex tensive ab initio calculations of a global potential [K. A. Peterson, S. Sk okov, and J. M. Bowman, J. Chem. Phys. 111, 2445 (1999)]. Initial state-sel ected and cumulative reaction probabilities to form each set of products fo r J=0 are calculated by a direct summation of the initial state-selected re action probabilities. We propose and test a simple energy-shifting approxim ation that relates the initial state-selected reaction probability for arbi trary j to the one for j=0. Extensions of standard J- and K-shifting method s are suggested and applied to both reaction channels. In doing this extens ion the adiabatic rotation approximation is used to determine the rotationa l barriers in the entrance and exit channels. The energy dependence of the reaction cross sections to form the two products is calculated for O(D-1)+H Cl(v=0,j=0) using J- and K-shifting and compared at two translational energ ies to results of quasiclassical trajectory calculations. The thermal rate constants for the two reaction channels are calculated from 200 to 400 K an d compared to experiment. (C) 2000 American Institute of Physics. [S0021-96 06(00)00939-9].